Zoe turned her go-kart and accelerated down the brightly lit race track. “Woohoo!” she yelled, pulling farther away from Ben.

There was no way Ben could catch up to his twin sister now. There was one more lap to go. Zoe would win this race for sure.

Just then, someone flagged Zoe down. “The track must be closing early,” Zoe said to herself. She maneuvered off the raceway and braked hard. She came to a stop a few feet from the woman with the flag.

Zoe was just taking off her crash helmet when Ben came screeching to a halt right behind her. He watched as Zoe ran over to the woman, recognizing her immediately.

“Erika!” Zoe cried out in excitement. She looked around to make sure that no one else was within earshot. “Do we have a new mission? Is that why you’re here?”

“Yes,” said Erika. “I’m here to take you straight to your destination.”

Ben and Zoe were by far the youngest operatives in WILD, a top-secret rescue organization run by their uncle, Stephen Fisher. Erika Bohn was his second-in-command. Whenever WILD received news of an animal in danger, Erika showed up suddenly, wherever Ben and Zoe were. Before they knew it, they’d be heading out for another WILD rescue mission.

Erika grinned. “Sorry I interrupted your race,” she said.

“No problem, Erika,” Ben said, grinning widely. “We’ll just call this last race a draw.”

“No we won’t!” said Zoe. “I was in the lead the entire —”

Zoe was cut off by a revving go-kart engine. Before she could speak, Ben zoomed away to return his go-kart.

Zoe rolled her eyes. “Boys,” she said.

* * *

A few moments later, they were all driving down the highway in Erika’s car toward a private airfield. Ben quickly sent a text message to their grandma, letting her know that they wouldn’t be home tonight.

Grandma took care of Ben and Zoe while their parents were working abroad as vets. She knew all about WILD, and was very proud of her brave grandchildren.

Zoe watched from the front seat as they passed the white, barren fields. Evergreen trees were lit briefly in the car’s headlights as they passed. “I wonder what kind of animal we’ll be helping this time,” she said.

“You know the drill,” said Erika. “In the glove compartment, you’ll find a clue from your uncle.”

Zoe reached into the compartment and pulled out a glass eyeball. Using a penlight she found inside, she inspected the eyeball. It had an orange and brown iris with a round, black pupil.

“It reflects the light,” she said, turning it in the beam. “So it’s probably a copy of a nocturnal animal’s eye.”

Ben reached over from the back. Zoe gave him the eye and the penlight. “And it’s big,” he said. “I bet it’s from a member of one of the wild cat species.”

“I agree,” said Zoe. “Let’s see what Uncle Stephen has to say.”

Ben gave her the eyeball. Zoe carefully placed it into a slot in the vehicle’s dashboard. Immediately, a small hologram of a man appeared in front of them. He wore a white lab coat and had a hat sitting on top of his messy hair.

“Greetings, my nephew and niece!” said Uncle Stephen. “Your destination for this mission is Africa.”

“It’s definitely not a tiger, then,” said Ben.

“Africa is a king-sized clue to the animal you’ll be rescuing,” Uncle Stephen’s hologram said. “Call me as soon as you’ve figured out the answer.”

The hologram disappeared.

“A king-sized clue,” repeated Zoe. “That has to mean —”

“The king of the beasts!” interrupted Ben. “Wow! We’re rescuing a lion. That’ll be exciting!” His eyes went wide. “And a little scary.”

“Your BUGs are under your seats,” Erika told them. “Go ahead and give your uncle a call with your answer.”

Ben and Zoe never went on a mission without their BUGs — the Brilliant Undercover Gizmos their uncle had invented. They looked like handheld video games, but had lots of wonderful applications, like satellite maps, communicators, and animal tracking devices. Zoe took her BUG, hit the call key for WILD HQ and turned on the speakerphone.

“Good evening, Ben and Zoe!” came their uncle’s voice. “Did you figure it out yet?”

“Yep,” said Zoe. “It’s a lion!”

“Well done,” said Uncle Stephen. “You’re headed to the Kalahari Desert in Namibia.”

“Awesome!” said Ben. “So what’s the mission this time, Uncle Stephen?”

“Here at HQ, we picked up a news report on a Namibian radio station,” Uncle Stephen said. “A lioness has been seen prowling around a local well for a few days. That well is the only source of clean water for the locals, and they won’t dare go near it because of the angry lioness.”

“Lionesses don’t usually live alone, do they?” asked Zoe.

“I don’t think this one is alone,” said Uncle Stephen. “There have been several reports of strange sounds coming up from the bottom of the well.”

“Did one of the lioness’s cubs fall down the well?” Ben asked.

“That’s the most likely explanation, yes,” said Uncle Stephen. “It’s probably calling out for its mother.”

Erika drove the car through an open gate toward a rough track. “That would also explain why the lioness won’t leave the area,” she added.

“Oh, that poor cub,” said Zoe.

“Don’t worry, sis,” Ben said. ”We’re going to rescue it!”

“And return it to its mother as soon as possible,” said Uncle Stephen.

Uncle Stephen’s voice grew serious. “Otherwise, the cub will soon starve to death,” he said. “We don’t know how long it’s been down the well, or if it’s injured. That’s why we’re flying you straight there.”

“We need to preserve as many Namibian lions as we can — especially the young ones,” Erika said. “Their numbers have been declining recently due to disease — and because of humans, unfortunately. People illegally hunt lions, and there have been several cases where lions were poisoned for being too close to farms.”

“You should land in Namibia in the morning — local time,” Uncle Stephen said. “Your equipment’s already been loaded onto the WILD Jet. There’ll be plenty of time on the journey for you to watch the desert training videos.”

“We learned about sandstorms in the climate chamber last time we were at WILD HQ,” Ben said, reminding their uncle.

“And that will come in very handy,” said Uncle Stephen. “But you also need to be able to survive ordinary desert conditions. The Kalahari is a dangerous place, so I’m glad you won’t be out there very long. Good luck. Over and out.”

Erika stopped the car next to a small plane idling on an airstrip. “You’ll be taking a vet’s kit with you in case the cub needs attention,” she said as they jumped out of the car. “And tranquilizer guns, of course.”

Ben nodded. “Good,” he said. “We don’t want the lioness eating us while we’re rescuing her cub!”

“How about ropes to climb down the well?” asked Zoe.

Erika nodded. “You know it,” she said. She swung open the door of the plane so the twins could climb aboard. “Inside, there’s also lightweight clothing that reflects the sun to help keep you cool. It’s summer out there — and extremely hot.”

“What’s our new gadget, Erika?” asked Ben. “Uncle Stephen always comes up with something new and amazing for our missions.”

Erika strapped herself into her seat. “Your uncle’s really excited about this one,” she said, adjusting several knobs on the jet’s console. “But you can’t see it until we get to Namibia.”

“Then what are we waiting for?” said Zoe. “Let’s fly!”